Transcript Valve Characteristics - Northern Calif Hawaii Nebb

Pressure Independent Control Valves
Flow Verification/Commissioning
Belimo’s Family of PI Control Valves
ePIV
PICCV
© Belimo University
2012, All Rights Reserved
Energy Valve
Pressure Independent Control Valve
What is a pressure independent control valve?
A PI Control Valve….
Is a 2-way control valve that supplies a precise flow at any given
control signal…
Regardless of pressure variations in a system.
It is not just a control valve and flow limiting circuit setter in the same
assembly!
Note:
Automatic or manual balance valves should NOT be used with PI
valves. If they are already installed they should be set WIDE
OPEN.
Pressure Independent Control Valve
Field Installed P/T port requirements
Additional P/T PORT for verification of 5 psi (11.5 ft
H20) minimum differential across the PI Valve.
Minimum ΔP across valve must be verified with PI valve
COMMANDED by DDC (or by programming tool) to design
flow, not manually positioned!
System Level Flow Verification
Step 1: Ensure all strainers are clean and bypass valves are closed.
Step 2: Command via DDC all PI valves to design flow. (Diversity
assumed at 100%.)
Step 3: Set distribution pump(s) to elevated speed by commanding
ΔP setpoint or pump speed directly.
Step 4: Find the “critical zone” (ie. the PI valve that has the least ΔP).
Step 5: Increase or decrease pump speed/ΔP setpoint until critical
zone has just over 5 psid (11.5 ft H20). The resulting ΔP at the system
sensor will be the optimum system ΔP setpoint.
Step 6: Verify total system flow is at design at main flow station (or by other
method).
Step 7: If flow is not within +/- 10% of design, start checking valves at terminal level,
starting with largest valve(s) first (voltage, control signal, strainer, etc.)
Terminal Level Flow Verification
• Belimo PI valves do NOT require that the entire
system be placed in full design flow. Each PI
valve flow can be verified individually with the
rest of the system under normal control.
1) Command valve assembly to design.
2) Verify 5 psid across PI valve assembly.
3) Verify coil flow as per usual method (coil ΔP
method, etc.)
Link for PI valve commissioning document:
www.piccv.com/pdf/PICCV_Application_Bulletin.pdf
Belimo Field Programming Tool
Field adjustable programming tool
allows basic setup to be
changed/modified based on initial or
changing needs of project without
hardware modification or change out.
Example: Change Orders or Tenant
Build outs.
No external power needed; no battery; powered
by actuator 24 vac. Just plug it into actuator.
Belimo PC Tool Software
Field Programming Software
allows changes/modifications
to setup in addition to
trending and diagnostic
capabilities.
Commissioning Documentation
Available upon request.
Questions?